A young girl journeys to Africa to find her father, an explorer who vanished in the jungle.
The obsessive scientist Dr. Miller is working on a matter-transmitter invention called the Paratron; a conspiratorial team of spies and no-goods pursue him to Alaska, trying to steal the device.
Prior to the United States' involvement in World War II, the masked vigilante Spy Smasher fights Nazi agents operating within the US, led by the treacherous sabotage leader codenamed The Mask.
Mota is a Martian representative, who has come to impose interplanetary law on the Earth (which has become too dangerous); opposing his authority is Kent Fowler, who resists the alien plot, without understanding its details.
An expedition arrives on an uncharted jungle island to rescue the local natives, led by a jungle boy, from a volcano that is about to erupt.
Escaped Prisoner 39013 impersonates the rich and influential Horace Granville, allowing him to create a variety of disasters. Fortunately, he is thwarted repeatedly by three daring circus daredevils.
Beyond Hell's Gate Pass is territory controlled by a man who calls himself King Carter; he uses a variety of schemes to prevent the railroad from being built, for fear it will finish his control of (what he considers) his land.
Beatrice Fairfax, the original advice-to-the-lovelorn reporter and her friend and not-so-secret admirer Jimmy Barton investigate calls for help and escape exotic perils and dangers. Episodes include exciting and fun stories of baby-napping, blackmail, jewel thievery, disguise, counterfeiting, and the long-unseen episode featuring entrancing cult starlet Olive Thomas and the real New York Yankees and Giants playing a game in the Polo Grounds.
The nefarious Dr. Fu Manchu searches for the keys to the tomb of Genghis Khan, in order to fulfill a prophecy that will enable him to conquer the world. His nemesi, Dr. Nayland Smith and his associates fight to keep the evil doctor from getting his hands on the keys. In 1943 the serial was edited together into a feature movie also called Drums of Fu Manchu.
Disaster seems imminent when scientists discover that the planet Mongo is about to crash into Earth. Luckily, heroic young Flash Gordon is on hand to lead an investigative mission into outer space and onto the speedily approaching planet. There, he and his best girl, Dale, who is along for the ride, learn that Ming, the devious ruler of Mongo, has purposely put the planet on a collision course with Earth, and only Flash can stop him.
The Phantom Rider helps Mary Grayson thwart a plot to steal her land.
The story of a boy, a dog, and a man. The boy discovers he is heir to a shipping line, and travels to Los Angeles, accompanied by inventor/radio operator Bob Whitlock and Irene Blaine. Their journey is aided by Pal, a wolf dog.
Sergeant MacLane of the Mounties investigates the disruptive activities of a bunch of troublemakers.
Famed aviator Bruce Gentry is working with scientist Andrew Benson, setting out to uncover the origin of a deadly secret weapon---an electronically controlled flying disc which can be directed at moving or stationary targets. The disc was master-minded by an enemy agent known only as "The Recorder" because...he speaks entirely via recordings. Aided by rancher Frank Farrell and his sister Juanita "Nita" Hodges, Gentry consistently foils "The Recorders" schemes, which are carried out by "The Recorder's" henchmen, Krendon, Allen and Chandler, including an attack on the Panama Canal.
Prospector Henry Tolliver disappears and his son "Wild Bill" Tolliver comes looking for him.
Government agents try to thwart smugglers, while some sort of plot unfolds, about a hidden treasure revealed by cursed coins.
Kit Cardigan seeks the killer of his father...among other plot threads leading up to the famous historical incident.
Jesse James wants to start a new life in a new location, but quickly finds himself wrapped-up in protecting townsfolk from the machinations of evil oilmen.
Government agents work to interfere with schemes to trick the Comanches into war with the Texans.
Before the outbreak of WWII, Nazi sympathizers plot to undermine America.